Baseline characteristics
| Characteristic | Vitamin D group | Placebo group | p-value |
| Subjects n Men | 71 59 (83) | 71 62 (87) | 0.482 |
| Age years | 68±9 | 68±8 | 0.649 |
| Smoking status | |||
| Current smokers | 13 (18) | 16 (23) | 0.288 |
| FEV1 L | 1.25±0.45 | 1.22±0.44 | 0.635 |
| FEV1 % pred | 45±16 | 43±14 | 0.508 |
| FVC L | 2.82±0.80 | 2.95±0.88 | 0.377 |
| FEV1/FVC ratio | 0.44±0.12 | 0.42±0.11 | 0.239 |
| DLCO % pred | 48±17 | 50±16 | 0.538 |
| GOLD stage | |||
| I | 1 (1) | 0 (0) | 0.319 |
| II | 21 (30) | 19 (27) | 0.715 |
| III | 32 (45) | 38 (54) | 0.317 |
| IV | 17 (24) | 14 (20) | 0.546 |
Baseline characteristics of vitamin D and placebo groups at randomisation. Both groups were matched for all given variables. Data are presented as n (%) or mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; GOLD: Global Initiative for Chronic Obstructive Lung Disease.